I´m going to be completely honest, I have literally no idea at all regarding Koitatsu or how much work Fujino does or does not put on each update regarding animations.
When I´m talking about it taking four years, it was with the assumption of Fujino continuing to release the game as he does now, with one big event happening every update, not just slapping his models on some pre-existing animation and calling it a day.
As things are right now, Fujino is barely capable of getting each monthly update out on time, with him talking more than once about how his (real) job was taking too much of him, so I imagine that the work that he has to do for each update is at the very least time-consuming.
(All that being said, I know an animator (Lanzfh) who has done a lot of SAO ntr vids, and that guy releases like 3 or 4 new animations each week. They aren´t all that great, but he certainly is on the grind at the very least.)